TRENTON — Exactly one year has passed since Gov. Chris Christie sat down for a chat on a late-night talk show, yukking it up with Jimmy Fallon while enjoying sky-high approval ratings in New Jersey and the nation.

The Republican governor will visit with Fallon again tonight, but a lot has changed since they last met.

While Fallon got a better job as host of "The Tonight Show," Christie’s job got tougher as the George Washington Bridge controversy cut into his popularity and made him the butt of late-night jokes.

The appearance will be Christie’s first foray into big TV spots that helped burnish his national image since the bridge scandal erupted. Political experts say it’s the biggest example yet that he is moving on from the controversy as he eyes a 2016 presidential campaign — even if the public and investigators are far from forgetting it.

"I think (Christie and his team have) concluded that the worst of Bridgegate is behind them," said Carl Golden, a former press secretary for Govs. Thomas H. Kean and Christie Whitman. "I don’t know if that’s true or not. But the environment is now ripe and ready for him to go back and do the kinds of public events and appearances that marked his administration from the beginning."

But last year, Democrats accused members of Christie’s inner circle of closing lanes on the bridge in September, causing heavy traffic in Fort Lee, because the borough’s Democratic mayor declined to endorse the governor for re-election. Emails later showed Christie’s deputy chief of staff appeared to know of the plan. Christie said he wasn’t involved but fired the aide and cut ties with his former campaign manager.

And the governor became a popular target of a slew of jokes from late-night hosts, including Fallon, who did a duet with Springsteen on a bridge parody set to the tune of "Born to Run."

As this unfolded, Christie didn’t take questions from the press for months — something Golden said showed "this was a matter of great concern to him."

Lately, it appears the Christie of old has returned. He has traveled across the country as chairman of the Republican Governors Association, raising more than $33 million for GOP candidates. He’s holding news conferences again, and has guested on sports-talk radio shows.

A recent Farleigh Dickinson University poll showed his approval rating among New Jerseyans has stabilized at 44 percent — though still a far cry from after Hurricane Sandy, when his numbers hovered around 70 percent.

Julian Zelizer, a political science professor at Princeton University, said tonight’s appearance is an attempt by Christie to rehab his image.

"I do think there is a sense the scandal is fizzling," Zelizer said. "This is a chance for him to reintroduce himself. At a minimum, it’s a way for him to test the waters. Are people only going to talk about Bridgegate or also talk about Chris Christie as a potential presidential candidate?"

Ross Baker, a political science professor at Rutgers University, likened it to Groundhog Day.

"Everybody is kind of crowding around the burrow to see if when the groundhog comes out, there will be more weeks of winter or not," Baker said. "It’s a tentative step."

Mike DuHaime, Christie’s chief political strategist, did not return requests for comment.

Mark Behan, an Albany, N.Y.-based crisis management expert, said Christie was wise to choose the affable Fallon over Stewart or Letterman, who might press him more on the scandal.

"The audience’s expectations are much different than the ones who watch ‘60 Minutes.’ " Behan said. "It makes him more human, more personable, and it gives him a chance to show off his sense of humor … (but) he has to be careful not to make too light of these issues."

Larry Sabato, a political science professor at the University of Virginia, said Christie’s move is similar to what Bill Clinton did after his disastrously long speech at the Democratic National Convention in 1988. Clinton, then the governor of Arkansas, later appeared on "The Tonight Show" when Johnny Carson was host.

"Carson welcomed him, then put a big hourglass on the desk to signal the segment was only a few minutes long," Sabato recalled. "(It was) hilarious, and the laughter helped."

Still, experts noted the bridge scandal will likely continue to hound Christie — especially if he does decide to run for the White House.

"It’s now part of his record," Zelizer said. "It will come back if he’s a presidential candidate. Part of the reason it’s faded is because he has kind of faded."